diff --git a/CHANGELOG b/CHANGELOG
index 13b3b1bce..75d351cf8 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -55,6 +55,7 @@ CHANGELOG Roundcube Webmail
 - Fix (again) bug where image data URIs in css style were treated as evil/remote in mail preview (#5580)
 - Fix bug where mail search could return empty result on servers without SORT capability (#5973)
 - Fix bug where assets_path wasn't added to some watermark frames
+- Fix so untagged COPYUID responses are also supported according to RFC6851 (#5982)
 
 RELEASE 1.3.1
 -------------
diff --git a/program/lib/Roundcube/rcube_imap_generic.php b/program/lib/Roundcube/rcube_imap_generic.php
index c46f9d36d..f1c87d562 100644
--- a/program/lib/Roundcube/rcube_imap_generic.php
+++ b/program/lib/Roundcube/rcube_imap_generic.php
@@ -3709,9 +3709,17 @@ class rcube_imap_generic
         // Parse response
         do {
             $line = $this->readLine(4096);
+
             if ($response !== null) {
                 $response .= $line;
             }
+
+            // parse untagged response for [COPYUID 1204196876 3456:3457 123:124] (RFC6851)
+            if ($line && $command == 'UID MOVE' && substr_compare($line, '* OK', 0, 4, true)) {
+                if (preg_match("/^\* OK \[COPYUID [0-9]+ ([0-9,:]+) ([0-9,:]+)\]/i", $line, $m)) {
+                    $this->data['COPYUID'] = array($m[1], $m[2]);
+                }
+            }
         }
         while (!$this->startsWith($line, $tag . ' ', true, true));